Best cabinet for a 416-8C (flat ferrite magnet), 511B, 902-8T and more

[morfeora]

Well guys, the things are moving slowly, but finally I got most of the parts for the cabinets from the cutting company (The sides for one cabinet were missing, I did not buy enough boards, but I already have another board at home, I will have o cut it by myself using my circular saw).

I make my wife to take this picture just you make myself an idea of how the woofer will look on that wood (Really on pictures is hard to imagine how big an Altec 620 cabinet is):


So far I am very excited, it seems that the cabinets on this wood will look fantastic! And looking at the picture, I think I will make the bass reflex port in the bottom of the cabinet, not in the front, I will look more elegant to my taste to leave only the woofer as object in the front of the cabinet... the wood looks very beautiful, a port in the front will affect too much the ascetics. As I write, I think I can create a port in the bottom and another one in the back, and to close one or another to experiment or to play according to the speaker placement in the room.





Next Monday I will cut the two sides that I am missing and, may be building a router guide to make the driver cuttings. (Oh yes, I just receive my new bosh "colt" palm router too ).

More soon,
Rodolfo

 

[twiiii]

The larger the cabinet the better the performance. I would mount them in walls with either the backs being totally open or maybe having closets behind the speakers with a lot of hanging clothes to break up the standing waves. That way you would get the best performance below 40 hz and possibly extending down to 20 HZ. All Altec and JBL woofer from that period would be considered high distortion woofers today. Modern woofers have totally different voice coil magnet, cone and designs with added magnetic shorting coils to reduce distortion over 15 db and lower in some instances. Modern JBL's would be a better choice. Mcintosh developed the design and patented it. But I know Magico, JBL, and others are using the technology with great success. JBL's latest HF drivers have any where from 70 to 90 % less distortion also. But I don't remember which ones at the moment. I prefer line arrays because you can get detail with lower distortions down to middle C and lower in some cases. They need much more power, but they are more revealing than horn systems with less distortion; but, they aren't cheap.

 

[morfeora]

The larger the cabinet the better the performance. I would mount them in walls with either the backs being totally open or maybe having closets behind the speakers with a lot of hanging clothes to break up the standing waves. That way you would get the best performance below 40 hz and possibly extending down to 20 HZ. All Altec and JBL woofer from that period would be considered high distortion woofers today. Modern woofers have totally different voice coil magnet, cone and designs with added magnetic shorting coils to reduce distortion over 15 db and lower in some instances. Modern JBL's would be a better choice. Mcintosh developed the design and patented it. But I know Magico, JBL, and others are using the technology with great success. JBL's latest HF drivers have any where from 70 to 90 % less distortion also. But I don't remember which ones at the moment. I prefer line arrays because you can get detail with lower distortions down to middle C and lower in some cases. They need much more power, but they are more revealing than horn systems with less distortion; but, they aren't cheap.

Thank you for your comments, I will try some day to put this woofers on a wall (Will have this in mind when my dream listening room could be build). So far you just make me think about playing with stuffin the cabinets I am building to make them bigger at least virtually and see what happens. I am also looking for modern JBL woofers around here, I will grab them once they appear on the second hand market... For me this just a starting, but I guess, and wish, I will be building many speakers from here to the end of my life.
Cheers.

 

[morfeora]

Hello friends, slowly slowly I am doing some progress.

I already have all the wood sides ready to be assembled, the bracing and corner woods are also in my hands.

But what I want to share with you today Is one of the little things I feel proud about.
I was able to change the dust cap for one of the Altec 416-8C woofers. I used isopropyl alcohol to soften the original glue and found locally a black glue used for shoe repair calle PL-285 I am pretty happy with the result.

In what I am no so happy is that the original dust cap is lighter that the one I put on. Almost one gram of difference... So the cone it self now is one gram heavier, I don't know if this will be audible to my ears, but for sure this change some the parameters of the woofer.

After some minutes applying the alcohol I started soften the glue using a plastic thin piece.




At first I did not believe the alcohol would work, bit it did.




After cleaning the entire cone with the alcohol, I proceed to glue the new dust cap.


This was the result... I am very happy with the resold because it was the second time I do this in my life, the first time I did not have the proper glue and the result was very ugly... This time I susceed. The glue was applied using a eye tear pot.. the one used for medicine that we need to put on our eyes, and after with a Chinese stick I pass again to make a thin layer of the glue.



Looks almost like original


But.... The difference in the weight of the dustcaps leave me thinking

The original:


The new one:


This is all for today guys... I will be back soon.

Cheers,
Rodolfo

 

[morfeora]

Hello folks,

Well after some time things have been starting to take shape. Assembling the first cabinet was a total trail and error, in the process I realized that didn't have the proper clamps to do it, so I was forced to use ratchets, I was at the beginning naive thinking strap clamps will be enough for the job. But before that, using the Joint Mate tool was very fun and easy.






Here is where everything started to complicate, the glue was applied already, but joints didn't tight correctly... only ratchets and some brute force were needed.:







At the end the first cabinet glued right with some minor gaps in some parts. Those will be sealed in the future, of course. Just to create myself and idea I put on top the 511B horn.

 

[morfeora]

After the first lesson on cabinet assembly, the second cabinet was better, and some tools were added to the "clamping" process. This way all the joints end up very tight.




After, for the very first time using a router... well, things did not end bad at all... just the cutting hole slightly bigger, but will be ok, like that.










For the front baffle I tried to be safe and bought 10 F clamps, very confident that that number would do the job properly... but no, now I know "you never have too many clamps", but any way I manage to do a good job with that.

 

[morfeora]

Well in this stage I was anxious to see how the cabinet will look with the woofer mounted, so I did the job and again, bring the 511B horn to see... this looks fantastic and was my first time seeing this beautiful and historical combination.





Don't worry guys, this will have the proper bracing inside.




Well, still there is a lot of work to be done, starting with gluing the front baffle of the second cabinet.
Regarding the finishing, I was thinking a lot regarding lacquer vs oil+beeswax, but two articles made me choose to use only a mixture of beeswax and turpentine.
The first article was from Lansing heritage, where JBL suggested applying linseed oil mixed with turpentine on a base of 3 parts of oil for one of turpentine. But reading around, I found an article from UK about how to properly treat old church furniture and wood decoration. They suggested applying a wax using ONLY turpentine and beeswax, without the oil. I tried that today and liked more that the mixture including oil. I haven't tried yet the mixture of only turpentine and linseed oil, but as I prefer a clear finish, I think turpentine+beeswax will be the winner.

This is a comparison of beeswax+olive oil+turpentine vs untreated wood:






Well, this is for now... more updates in the future. I hope you all be well.
Cheers!
Rodolfo

 

[bowtie427ss]

I'd have put all of that effort into the 515's, and sent the flat magnet 416C's down the road.

Did somebody suggest that building cabinets from solid lumber was a good idea?

Maybe i have missed the point, and this exercise is all about cosmetic appearance.

 

[morfeora]

I really hope to rebuild the 515B some time in the future and build another cabinets for them. I like to think this are not going to be the only cabinets I make.

As I did not listen to any Altec before, I wanted to give it a try to the 416-8C. I have read around a lot and some say the Alnico is the only one that sounds good, but also read others telling there was no difference when listening one and another on the Model 19. So I am not losing anything listening to these.

About the cabinet materials, was a lot of things... Ascetic one... The other one just try and play. The next cabinets I am going to build I know now, for sure will be MDF.

 

[Leben]

I’m enjoying following your build. Looks great!

 

[morfeora]

I’m enjoying following your build. Looks great!

Thank you Leben!

 

[bowtie427ss]

As I did not listen to any Altec before, I wanted to give it a try to the 416-8C.

The thing with the 416-8C is that there are several variants, and they all sound different. The GPA version is said to be the best, and indeed is the only version to use a copper shorting ring in the motor structure.

Altec was forced to quickly switch to ferrite motors in 1979 due to Cobalt shortages forced by the civil war in Zaire. They would add the shorting ring to the ferrite 515's, and 604's in fairly short order. But, Altec was also going through corporate problems in this time period, and would fall under ownership by the parent corporation of Electrovoice, and they wanted the competition Altec presented, gone. That probably ended most development of Altec products, at least for the time being.

About the cabinet materials, was a lot of things... Ascetic one... The other one just try and play. The next cabinets I am going to build I know now, for sure will be MDF.

Regardless of the material used, don't overlook the importance and benefits of internal bracing.

 

[mvandyke]

Looks great and good effort on putting the speakers together. The finish will really bring out the beauty of the wood.

What x-overs will you be using?

 

[morfeora]

The thing with the 416-8C is that there are several variants, and they all sound different. The GPA version is said to be the best, and indeed is the only version to use a copper shorting ring in the motor structure.

Altec was forced to quickly switch to ferrite motors in 1979 due to Cobalt shortages forced by the civil war in Zaire. They would add the shorting ring to the ferrite 515's, and 604's in fairly short order. But, Altec was also going through corporate problems in this time period, and would fall under ownership by the parent corporation of Electrovoice, and they wanted the competition Altec presented, gone. That probably ended most development of Altec products, at least for the time being.

Regardless of the material used, don't overlook the importance and benefits of internal bracing.

Thank you for the piece of history, I was aware of the switching to ferrite by Altec, but it is the first time I heard about the copper shorting ring (or Faraday ring). I already did a search, and it was amusing and interesting to learn about it and its use and how it improves the performance of a speaker distortion and sensitivity. Very interesting!! So far my options are limited to try this 416-8C, mainly because I so a bit complicated to buy and ship to Colombia the 515B recone kit (I am afraid od this delicate boxes to be damaged in the trip), any way I hope to figure out that some day in the short time. Sincerely I am not very optimistic thinking this sound will be out of this world, I am mainly curious about how this will sound. Any way this is what passionate me, to check how things sounds, and this goes for recordings, electronics (vintage so far) and speakers.

Regarding of internal bracing, yes, I plan to do all the bracing as Altec plans for the 620 dictates. I guess that will be enough to eliminate the unwanted panel resonances. I am even considering adding bitumen to the internal sides. Do you think guys this is worth it, or is not necessary?

 

[morfeora]

Looks great and good effort on putting the speakers together. The finish will really bring out the beauty of the wood.

What x-overs will you be using?

Thank you! Yes, I am very curious about how the finish will end up. I am trying and still want to check how the mixture of linseed and turpentine will looks, I feel it will be to dark for my taste. For crossover, I will start active using my Behringer DCX2496. So far I only have a Denon 2800 power amp, a Kenwood KA-907 and a pair of Kenwood KA-7100 (I use these as vertical bi amping). This system is in construction, so I do not have any amp for these speakers... I think the Scott 222 I have to repair will be a good match, but haven't start to check that amp yet (Seams an original output transformer in missing, bad thing). In the future, I would love to build a good passive crossover, if the sound of these speakers really motivates me.

 

[morfeora]

This was the progress of today. The front baffle for the second cabinet is ready and a test for the possible finish was done using only a mixture of beeswax+turpentine (without oil).
This time I use a pair of Wetzler claps borrowed to me by my old friend Carpentier... this clams could be from 1926 when the Wetzler company started in NY.










The Cabinets are ready for the internal bracing:


These are the two test for the finish. One beeswax+turpentine, the other one beeswax+turpentine+olive oil. It's not so clear in the picture but beeswax+turpentine looks better to me and also show a bit more the details of the wood but not creating so too much contrast.



All for today guys, More soon.
cheers!

 

[RonSSNova]

Nice job on the dust caps. I should have read this before doing mine, I did not realize alcohol would soften the glue.
I just did mine an hour ago.

Bowtie is smart about the Altec stuff. If I would have known about the 416-8C vs the 8B many years ago, I would have kept the 8B's and cone kits for my Model 19's. They came with 8C's, so had them reconed with GPA kits and used those.

Keep having fun!

 

[morfeora]

Nice job on the dust caps. I should have read this before doing mine, I did not realize alcohol would soften the glue.
I just did mine an hour ago.

Bowtie is smart about the Altec stuff. If I would have known about the 416-8C vs the 8B many years ago, I would have kept the 8B's and cone kits for my Model 19's. They came with 8C's, so had them reconed with GPA kits and used those.

Keep having fun!

Hi Ron, thank you! Beautiful set up you have there in your avatar. At the beginning I was skeptical about the isopropyl alcohol to soften the glue, most of the suggestions were toluene. But leaving the alcohol for some minutes on the glue and started to work, think is better than toluene because it is less aggressive. I can guess that even when you have 8C's on your 19's you have plenty of listening pleasure to have them for so many years. Am I right?

 

[RonSSNova]

Oh sure they do. But I'd sure like to have a mint pair of 416-8B to compare to. My guess is the 8C's would be for sale.
Sadly, the prices on this stuff have gone insane. If I wouldn't have sold various stuff I've owned over the last 40 years, I could pad my retirement funds! But water under the bridge, right?

Nice for me to see young folks having fun with this old stuff.

 

[morfeora]

Oh sure they do. But I'd sure like to have a mint pair of 416-8B to compare to. My guess is the 8C's would be for sale.
Sadly, the prices on this stuff have gone insane. If I wouldn't have sold various stuff I've owned over the last 40 years, I could pad my retirement funds! But water under the bridge, right?

Nice for me to see young folks having fun with this old stuff.

Oh yes! But "fun" falls short Ron. There are nights that I have hard to fall sleep because I can't stop thinking about speakers, this is really a big and a joyful passion to me.

I have been reading all I was able found about this dilema around the 8Bs, 8Cs, alnico and ferrite motors. I some place read some who have in one Model 19, I think in one side 8B and in the other 8C, saying he wasn't able to hear a difference when doing comparations... Might be this the same Bowtie was saying, that some 8Cs were well build and others don't... Might be you have the luck of having the good ones as I hope I do.

So far I am very excited to listen to them once finish, I have everything, just not much time to keep working. My beautiful companion takes most of my free time.





But to read you saying that you have a lot of other stuff over 40 years and you got you model 19 and enjoys them still, well really motivates me... Because I am a little bit afraid of been disappointed with the sound.
From my side Ron, is wonderful to have the opportunity, here and in person as I did with my now very good friend @Bratwurst7s, to share my passion with you guys that have the been enjoying this through the history it self of this marvelous developments of our humanity. So, thanks for sharing your 40 years here... This time with me.

PD: hope your retirement is already paid in other ways Ron